The objective is to determine whether the enhanced rate of glucose utilization exhibited by virus transformed cells is primarily due to an increased rate of glucose transport into the cell, or due to elevated levels and/or activity of enzymes involved in glucose metabolism. The uptake of non-metabolizable glucose analogs, including those that can be phosphorylated, such as 2-deoxy-D-glucose, and those that cannot, such as 3-0-methyl-D-glucose and 6-deoxy-D-glucose, will be measured in normal mouse cells (Balb/c 3T3) and mouse cells transformed with SV40 virus and with a murine sarcoma virus. In transport studies with 2- deoxy-D-glucose, intracellular levels of both free sugar and phosphorylated sugar will be determined, to determine whether enhanced levels of sugar phosphates in transformed cells arise from the activity of intracellular kinases, or through the activity of a possible phosphorylative transport system. Also, to establish whether apparent increased sugar transport in transformed cells is specifically due to the presence of the viral genome, rather than loss of density-dependent inhibition, rates of transport of sugars in transformed cells will be compared with normal cells both before and after cell confluency is reached, and with cells that carry no virus, but do not show density- dependent inhibition (3T6 cells).